Tightening device



Oct. 5,1937. H. STANLEY ET AL 2,094,635

.TIGHTENING DEVICE Filed May 8, 1935 Patented Oct. 5, 1937 UNITED STATES PATENT OFFICE TIGHTENING DEVICE Application May 8, 1935, Serial No. 20,446

8 Claims.

This invention relates to tightening devices and is particularly applicable to tightening devices for creating and maintaining tension upon strings such as are used in musical instruments, upon wires or other relatively small and high tensional filaments.

An object of the invention is to provide an improved tensioning device.

Another object is to provide an improved tensioning device which will receive and inclose the end of the strings of musical instruments.

Another object is to provide an improved tensioning device which will firmly hold strings or filaments subjected to relatively high tension.

Another object is to provide an improved tensioning device which may be easily and economically manufactured.

Another object is to provide an improved tensioning device which will be easy of operation.

Other objects will hereinafter appear.

The invention will be better understood from the description of one practical embodiment thereof, illustrated in the accompanying drawing, in which;

Figure l is a perspective View of the head and outer end of the neck of a stringed musical instrument, equipped with tightening devices embodying the invention, a guitar having been chosen for purposes of illustration; and

Figure 2 is a fragmentary sectional View taken on the line II-II of Figure l.

The present tendency in string musical instruments is away from strings of the type made of gut or other animal or vegetable fiber and toward metal strings, such as are used in the piano, and which generally are made of steel, with or without wrapping, depending upon the pitch of the tone desired.

The use of metal strings introduces two problems which were not present with gut or similar strings; one, the strings, due to their greater weight, must be strained toa much higher tension for a given note; and two, the ends of the wires, being stiff but of small diameter, are sharp and produce painful cuts and scratches and the like when one grips the head of an instrument, as is done in adjusting or changing the strings.

The higher tension requires that the strings be much more firmly held than was previously necessary, as very slight amounts of slippage cause them to become seriously out of tune.

In Figure 1, the invention is shown as applied to the head of a guitar, the neck of the guitar being indicated at I, while the wooden extension or head is indicated at 2. At the juncture of the head and neck is a nut 3 which is notched for the reception of the strings 4.

The remote end of the strings, it will be understood, are secured to the body of the guitar in any desired or well known manner. These parts therefore are not illustrated.

The upper ends of the strings are held by tightening devices embodying the present invention, and which are shown as arranged in two groups, one on each side of the wooden head, each group having means for tightening three of the six strings of the guitar. The number and arrangement can, of course, be readily varied by anyone skilled in this art to adapt the devices to any other type of instrument.

These tightening devices each are carried by a base plate 5, secured to the head of the guitar by screws 6, upon which plates are mounted the individual tightening mechanisms.

Each mechanism consists of a pin 1 supported in an aperture in the base 5 and in holes 8 and 9 formed in the wooden head. The pin between these holes spans a slot it formed through the head to permit the strings to reach the pins.

The outer end of each pin is squared as indicated at H, and on this squared portion is mounted a worm wheel l2, secured to the pin by screw [3 threaded into the end of the pin. The worm wheel meshes with a worm l4 carried by shaft l5 supported in bearings formed in lugs l6 integral the base plate 5.

The lower end of the shaft I5 is provided with a handle or flattened button ll by which the shaft may be conveniently rotated. The worm I4 is of sufficiently low pitch as to be self-locking or non-reversible and therefore prevents any unwinding of the string by accidental rotation of the pin 1.

The pin 1 has formed into its outer surface a generally V-shape-d annular groove l8 and is pierced from its inner end to the adjacent wall of this groove by a hole, hollow, or bore Hi, this hole entering the groove near or at its bottom. The bore I 9 is continued across the groove to provide a notch lSd to facilitate starting the string into the bore. One side of the groove is relatively steep as indicated at and may even be perpendicular to the axis of the pin or very nearly so.

The operation of the device is as follows: The

operator inserts the end of the wire string into the hole or bore l9 illustrated most clearly in Figure 2. He then rotates the handle [1, thus, through the worm and worm wheel, rotating the pin, this rotation, in the devices illustrated in Figure 1, taking place in a clockwise direction.

The instant any tension is placed upon the string, this string is drawn down into the bottom of the notch l8 and pressed or wedged against side 20 thereof, causing'a string to take a sharp bend at the point where it passes from the bore to the notch. While the pin is rotated'through one'revolution', a single turn or convolution 4a of string is formedin the bottom of the groove. Further rotation of the pin causes the next turn or convolution 4b to rest upon the exterior of the first convolution, and tension upon this second turn forces the first convolution more firmly into the bottom of the groove, due to the steepness of the side wall 26 of the notch.

Thus, two types of gripping action are obtained; one, the string is firmly anchored by the set imparted to it at the point where it enters bore l9, where it is formed into a kind of hook; and two, a snubbing action is provided and augmented by the overlying convolutions, forcing the innermost tightly against the walls of the notch..

The greater the tension which is applied to the string, the tighter it is gripped.

The holding of the string is found to be" very effective even though the string is of much smaller diameter t'han the bore, so that with a bore large enough to accommodate the largest strings that may bewanted, the smallest strings may likewise be firmly held.

Asthe end of the string is enclosed within the bore, and as the inner end of this bore is, in turn, enclosed within the wooden head, it is apparent that the strings cannot project to scratch or stick into the fingers of the operator.

While we have described the illustrated embodiment of our invention is some particularity, obviously many other embodiments, variations and modifications will readily occur to those skilled in thisart, and we do not therefore limit ourselves to the'precise details shown and decribed,; but claim as our invention all embodiments, variations and modifications thereof coming within the scope of the appended claims.

We claim: 7 r

1. A filament tensioning device comprising, in combination with a musical instrument having a slotted head provided with rotating means having a mechanical advantage, a pin spanning said slot and having one end enclosed with'said head and rotatable about its axis by said rotating means, the pin having a V-shaped annular notch in its exterior and within the slot, and a bore extending from said notch and terminating at the end of the pin enclosed within the head 2. A filament tensioning means comprising in combination with rotating means providing a mechanical advantage, a pin rotatable about its axis tended to be wound upon the pin and the bottom of the groove being of less width thanthe diameter of the filament.

4. A filament tensioning device comprising a pin rotatable about its axis and having a V- shaped groove, the depth of the groove being greater than the diameter of the filament intended to be wound upon the pin. 7

5. A filament tensioning device comprising a pin rotatable about its axis and having an annular groove, and a hollow communicating with said groove and adapted to receive the end of a string, the hollow extending from said groove to one end of said pin, and enclosing means adjacent the end of said hollow remote from said groove.

6. A filament tensioning device comprising a pin rotatable about its axis and having an annular groove, said pin also having an unobstructed hollow of substantial length communicating with said groove and adapted to receive the end of a string, the hollow extendingfrom said groove to one end of said pin, and enclosing means adjacent the end of said hollow remote from said groove, the juncture of the hollow and groove providing an abrupt edge.

7. A filament tensioning device comprising a pin rotatable about its axis and having an annular groove of greater depth than the diameter of a string intended to be used therewith, the bottom of the groove being of less width than the diameter of the string, said pin also having a hollow extending lengthwise of the pin and opening into the bottom of said groove.

8. A filament tensioning device comprising a pin rotatable about its axis, means for rotating the pin associated with one end thereof, a V- shaped annular groove in the exterior of said pin, said pin also having a hollow extending lengthwise of the pin opening into said groove, the hollow terminating at the end of the pin remote from said winding means.

HARRY STANLEY. VINCENT J. MOIR. 

